Presser foot lifting device of sewing machine

Abstract

The utility model belongs to the technical field of sewing machines, and particularly relates to a presser foot lifting device of a sewing machine, which comprises a presser foot, a connecting rod assembly, a presser foot lifting transmission mechanism, a cam and a servo motor which are assembled on a machine head, the presser foot lifting transmission mechanism comprises an L-shaped swing rod and a moving rod, and the L-shaped swing rod is rotatably arranged in the machine head through a rotating rod and connected with the connecting rod assembly. The movable rod is arranged in a sliding mode through a limiting block, one end of the movable rod is provided with a roller abutting against the arc-shaped driving face on the circumferential side of the cam, the movable rod is in transmission connection with the L-shaped swing rod through a connecting block and a limiting connecting rod, a first tension spring is arranged between the movable rod and the limiting block, and a second tension spring is arranged between the connecting block and the L-shaped swing rod. According to the device, the operation is quiet, the lifting height of the presser foot can be accurately adjusted, the action speed of the presser foot can be flexibly adjusted, the sewing quality and efficiency are improved, and the stable operation of the device is guaranteed.

Description

Technical Field

[0001] This utility model belongs to the field of sewing machine technology, specifically a device for raising the presser foot of a sewing machine. Background Technology

[0002] Sewing machines are essential equipment for sewing clothing and fabrics. They can quickly and accurately sew fabrics together and are widely used in the large-scale production of clothing, bags, etc. They greatly improve sewing efficiency and are an indispensable tool in the textile and apparel industry. The presser foot device plays a key role in the sewing machine. It can easily lift the presser foot to facilitate changing fabric, adjusting its position, or threading. When pressed down, it can flatten and fix the fabric, ensuring that the fabric is fed smoothly during the sewing process, making the stitches even and neat, and improving sewing quality and efficiency.

[0003] The existing presser foot lifting mechanism is mainly composed of the following parts: electromagnet, armature, spring, presser foot rod, presser foot, etc. Its working principle is: when the electromagnet is energized, it generates a magnetic field, which attracts the armature to move. The armature drives the presser foot rod to rise against the elastic force of the spring, thereby lifting the presser foot. When the electromagnet is de-energized, the magnetic field disappears, and the elastic force of the spring causes the presser foot rod and presser foot to descend, and the presser foot presses down on the fabric.

[0004] The existing presser foot lifting mechanism has the following drawbacks: Traditional devices are noisy during operation. The electromagnets generate noticeable electromagnetic noise and mechanical impact sounds when engaging and disengaging during operation. In home settings, this can easily disturb other family members. In clothing workshops and similar locations, the continuous noise can also interfere with the operator, affecting their work performance and concentration, leading to a decreased work experience. Furthermore, the traditional device's adjustment of the presser foot lifting height is rather coarse, making it difficult to precisely adapt to fabrics of different thicknesses. When handling thin silk fabrics, if the presser foot is raised too high, the fabric may shift or wrinkle during sewing. When handling thick denim fabrics, if the presser foot is raised too low, feeding difficulties may occur, severely impacting sewing quality and efficiency. Therefore, this paper proposes a presser foot lifting device for sewing machines to address these issues. Utility Model Content

[0005] To overcome the shortcomings of existing presser foot lifting mechanisms, a presser foot lifting device for sewing machines is proposed.

[0006] The technical solution adopted by this utility model to solve its technical problem is as follows: The sewing machine presser foot lifting device of this utility model includes a presser foot assembled on the machine head and a linkage assembly for lifting the presser foot in conjunction with the machine head. The machine head is provided with a presser foot lifting transmission mechanism that is connected to the linkage assembly in a transmission manner, and a cam for driving the presser foot lifting transmission mechanism to lift the presser foot. The circumference of the cam is provided with an arc-shaped driving surface for adjusting the height of the presser foot lifting.

[0007] Preferably, the lifting foot transmission mechanism includes an L-shaped swing arm rotatably mounted inside the machine head via a rotating rod, with one end rotatably connected to a connecting rod assembly, and also includes a movable rod slidably mounted via a limiting block, with one end of the movable rod being drively connected to the L-shaped swing arm.

[0008] Preferably, one end of the moving rod is fitted with a roller via an assembly block, and the roller abuts against the arc-shaped driving surface.

[0009] Preferably, a first tension spring is fitted between the moving rod and the limiting block to ensure that the roller always abuts against the arc-shaped driving surface.

[0010] Preferably, a connecting block is fitted on one end of the movable rod that is connected to the L-shaped swing rod, and a limiting connecting rod is fitted on the connecting block. One end of the L-shaped swing rod is slidably disposed in a groove opened on the limiting connecting rod.

[0011] Preferably, a second tension spring is fitted between the connecting block and the L-shaped rocker arm to ensure that the end of the L-shaped rocker arm located in the slide groove always abuts against the slide groove.

[0012] Preferably, the linkage assembly includes a first linkage rotatably connected to an L-shaped rocker arm, and a second linkage rotatably connected to the first linkage and rotatably mounted on the machine head via a rotating rod. A linkage column cooperating with the second linkage is provided on one side of the pressure foot, and the pressure foot is slidably mounted on the machine head via a spring.

[0013] Preferably, a servo motor for driving the rotation of the cam is mounted on one side of the machine head, and the servo motor is controlled by a controller set on the machine head.

[0014] Preferably, a manual control lever for driving the L-shaped rocker arm to rotate is rotatably mounted on the L-shaped rocker arm, and the bottom end of the manual control lever extends out of the machine head and passes through the worktable.

[0015] The beneficial effects of this utility model are:

[0016] 1. The presser foot lifting device of this utility model operates quietly, which can effectively reduce noise interference. When used in a home environment, it will not disturb other family members. In places such as clothing studios, it can also create a quiet and comfortable working atmosphere, allowing operators to focus more on sewing work and improve the work experience.

[0017] 2. It can precisely adjust the height of the presser foot. Whether it is a thin silk fabric or a thick denim fabric, the presser foot can be adjusted to a suitable height according to actual needs. This greatly improves the applicability of sewing. Operators can place and adjust the fabric more conveniently and avoid problems such as fabric wrinkles and uneven sewing caused by unsuitable presser foot height, thus improving sewing quality.

[0018] 3. The speed at which the presser foot is raised and lowered can be flexibly adjusted according to sewing needs. When performing fast sewing operations, the presser foot can be raised and lowered quickly to improve work efficiency and meet the needs of large-scale production. When performing complex and delicate sewing operations, the presser foot can be controlled slowly and steadily to facilitate more precise control of the fabric position and sewing process, ensuring the fineness and accuracy of the sewing. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the present invention and form part of this application, illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the present invention and do not constitute an undue limitation thereof. In the drawings:

[0020] Figure 1 This is a perspective view of the entire utility model;

[0021] Figure 2 yes Figure 1 Enlarged view of the structure at point A in the middle;

[0022] Figure 3 This is a three-dimensional structural view of the pressure foot, connecting rod assembly, and pressure foot lifting transmission mechanism in this utility model;

[0023] Legend:

[0024] 1. Machine head; 2. Presser foot; 201. Linkage column; 3. Linkage assembly; 4. Presser foot lifting transmission mechanism; 401. L-shaped swing arm; 402. Moving rod; 403. Assembly block; 404. Roller; 405. First tension spring; 406. Connecting block; 407. Limiting connecting rod; 408. Slide groove; 409. Second tension spring; 4010. Limiting block; 5. Cam; 501. Arc-shaped drive surface; 6. Servo motor; 7. Manual control lever. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0026] Specific implementation examples are given below.

[0027] Please see Figures 1-3The present invention discloses a presser foot lifting device for a sewing machine, comprising a presser foot 2 mounted on a sewing head 1, and a linkage assembly 3 for lifting the presser foot 2 in conjunction with the sewing head 1. The sewing head 1 is provided with a presser foot lifting transmission mechanism 4 that is hygienically connected to the linkage assembly 3, and a cam 5 for driving the presser foot lifting transmission mechanism 4 to lift the presser foot 2. The cam 5 is provided with an arc-shaped driving surface 501 on its periphery for adjusting the lifting height of the presser foot 2. A servo motor 6 for driving the cam 5 to rotate is mounted on one side of the sewing head 1. The servo motor 6 is controlled by a controller provided on the sewing head 1.

[0028] The lifting foot transmission mechanism 4 includes an L-shaped swing arm 401 rotatably mounted inside the machine head 1 via a rotating rod, with one end rotatably connected to the connecting rod assembly 3. It also includes a movable rod 402 slidably mounted via a limiting block 4010. One end of the movable rod 402 is drive-connected to the L-shaped swing arm 401. A roller 404 is mounted on one end of the movable rod 402 via an assembly block 403, and the roller 404 abuts against the arc-shaped driving surface 501. A connecting block 406 is mounted on the end of the movable rod 402 connected to the L-shaped swing arm 401. A limiting connecting rod 407 is mounted on the connecting block 406. The end of the L-shaped swing arm 401 slides... The cam 5 is rotatably mounted in a groove 408 on the limiting connecting rod 407. The connecting rod assembly 3 includes a first connecting rod 301 rotatably connected to the L-shaped swing rod 401, and a second connecting rod 302 rotatably connected to the first connecting rod 301 and rotatably mounted on the machine head 1 via a rotating rod. A linkage column 201 cooperating with the second connecting rod 302 is provided on one side of the presser foot 2. The presser foot 2 is slidably mounted on the machine head 1 by a spring. During operation, when the sewing machine needs to lift the presser foot, the controller sends a command to the servo motor 6. The servo motor 6 outputs power to drive the cam 5 to rotate. The arc-shaped driving surface 501 on the periphery of the cam 5 rotates with the cam 5. Changes in the contour shape will generate thrust of different directions and magnitudes on the opposing roller 404. The roller 404 is mounted on the assembly block 403 at one end of the moving rod 402. Under the action of the thrust, the roller 404 drives the moving rod 402 to move linearly along the direction defined by the limiting block 4010. During the movement of the moving rod 402, it forms a transmission relationship with the L-shaped swing rod 401 through the connecting block 406 and the limiting connecting rod 407. Since the L-shaped swing rod 401 is rotatably mounted in the machine head 1 through the rotating rod, when the moving rod 402 moves upward, it will cause the L-shaped swing rod 401 to rotate around the rotating rod. When the L-shaped swing rod 401 rotates, it interacts with the machine head 1. The rotating end of the linkage assembly 3 will drive the first linkage 301 to move. The first linkage 301 will then pull the second linkage 302 to rotate around the rotating rod mounted on the machine head 1. During the rotation of the second linkage 302, it will interact with the linkage column 201 on one side of the presser foot 2, so that the presser foot 2 will overcome the elastic force of the spring and lift the presser foot 2 upward. When the presser foot 2 needs to be pressed down, the servo motor 6 will continue to drive the cam 5 to rotate, and the roller 404 will fall into the arc groove on the arc drive surface 501. The roller 404 will no longer be pushed. At this time, under the action of the spring's restoring force, the presser foot 2 will move downward along the sliding track on the machine head 1 and press the fabric again.

[0029] This invention's presser foot lifting device significantly reduces noise compared to electromagnets, effectively improving the sewing machine's working environment. It is particularly suitable for noise-sensitive home use and quiet environments such as garment workshops. Furthermore, by precisely controlling the rotation angle of the servo motor 6 via a controller, the arc-shaped drive surface 501 on the cam 5 can rotate different distances. Since the contour shape of the arc-shaped drive surface 501 is directly related to the presser foot 2 lifting height, precise adjustment of the presser foot 2 lifting height can be achieved. Whether sewing thick, multi-layered fabrics or delicate operations on thin fabrics, this adjustment allows for precise control. The height of presser foot 2 is adjusted to facilitate the placement and adjustment of fabric, improving the applicability and ease of operation in sewing. Simultaneously, the speed of servo motor 6 can be adjusted by the controller according to actual sewing needs, and the rotation speed of cam 5 is directly proportional to the lifting or lowering speed of presser foot 2. During rapid sewing operations, the speed of servo motor 6 can be increased, causing cam 5 to rotate quickly, enabling rapid lifting and lowering of presser foot 2 and improving work efficiency. During complex and delicate sewing operations, the speed of servo motor 6 can be reduced, allowing presser foot 2 to lift and lower slowly, facilitating more precise control of fabric position and the sewing process, and ensuring sewing quality.

[0030] Furthermore, a first tension spring 405 is fitted between the moving rod 402 and the limiting block 4010 to ensure that the roller 404 always abuts against the arc-shaped driving surface 501. During operation, the first tension spring 405 is installed between the moving rod 402 and the limiting block 4010. In the initial state, the first tension spring 405 is in a certain tension state, thereby generating a pulling force on the moving rod 402 in the direction of the cam 5. When the cam 5 rotates, the arc-shaped driving surface 501 pushes the roller 404 to move the moving rod 402 away from the cam 5. When cam 5 moves in a certain direction, the first tension spring 405 is further stretched, increasing the tension. As cam 5 continues to rotate, the thrust of the arc-shaped drive surface 501 on the roller 404 decreases. Under the tension of the first tension spring 405, the moving rod 402 is pulled back in time, ensuring that the roller 404 is always tightly fitted to the arc-shaped drive surface 501, ensuring that there is no gap or separation in the contact between the two. This allows the movement of cam 5 to be accurately transmitted to the moving rod 402, thereby driving the subsequent lifting of the pressure foot. Action; During the long-term continuous operation of the sewing machine, due to factors such as changes in fabric thickness and sewing speed adjustments, the contact force and motion state between the cam 5 and the roller 404 will constantly change. The cooperation of the first tension spring 405 can maintain the tight contact between the roller 404 and the arc-shaped drive surface 501 under various working conditions, effectively preventing the roller 404 from disengaging from the arc-shaped drive surface 501 due to vibration, impact, etc., preventing malfunction or failure of the presser foot lifting device, and greatly improving the reliability and stability of the entire presser foot lifting device. If there is a gap or disengagement between the roller 404 and the arc-shaped drive surface 501, it will cause the movement of the moving rod 402 to be inaccurate, which will affect the action accuracy of the L-shaped swing rod 401, the connecting rod assembly 3, and the presser foot 2. The first tension spring 405 ensures that the two are in continuous and stable contact, so that the movement of the cam 5 can be accurately converted into the lifting and pressing action of the presser foot 2, ensuring that the height of the presser foot 2 is consistent each time it is lifted and pressed down, improving the accuracy of presser foot control during sewing, and helping to improve sewing quality.

[0031] Furthermore, a second tension spring 409 is fitted between the connecting block 406 and the L-shaped rocker arm 401 to ensure that one end of the L-shaped rocker arm 401 located in the slide groove 408 always abuts against the slide groove 408. During operation, the second tension spring 409 is installed between the connecting block 406 and the L-shaped rocker arm 401, and initially has a certain amount of tension, generating a pulling force on the L-shaped rocker arm 401 that causes one end of the L-shaped rocker arm 401 located in the slide groove 408 to move towards the bottom of the slide groove 408. When the moving rod 402 is driven by the cam 5... During movement, the L-shaped rocker arm 401 rotates around the rotating rod via the connecting block 406 and the limiting connecting rod 407. The end of the L-shaped rocker arm 401 that slides within the slide groove 408 is subjected to a force from the moving rod 402. At this time, the tension of the second tension spring 409 ensures stable sliding of the L-shaped rocker arm 401 within the slide groove 408, preventing wobbling or deviation within the slide groove 408. This ensures a stable and reliable transmission relationship between the moving rod 402 and the L-shaped rocker arm 401, allowing the force to be accurately transmitted from the moving rod 402. The transmission is transmitted to the L-shaped swing arm 401, which in turn drives the connecting rod assembly 3 and the presser foot 2 to complete the corresponding actions. In the transmission process of the presser foot lifting device, the L-shaped swing arm 401, as a key transmission component, directly affects the performance of the entire device due to the stability of its movement. The setting of the second tension spring 409 effectively eliminates the gaps and instabilities that may occur in the L-shaped swing arm 401 within the slide groove 408, making the transmission between the moving rod 402 and the L-shaped swing arm 401 smoother. This reduces energy loss and action errors caused by instability of the transmission components, ensuring the stable operation of the presser foot lifting device during long-term use. This ensures that the rotation angle and movement trajectory of the L-shaped swing arm 401 are highly consistent each time the moving rod 402 drives the L-shaped swing arm 401. This consistency ensures that the connecting rod assembly 3 drives the presser foot 2 to lift and press down in the same way each time, avoiding inconsistent action of the presser foot 2 due to transmission instability. This is of great significance for ensuring sewing quality and production efficiency, and is particularly suitable for industrial production scenarios with high sewing precision requirements.

[0032] Furthermore, a manual control lever 7 for controlling the rotation of the L-shaped rocker arm 401 is rotatably mounted on the L-shaped rocker arm 401. The bottom end of the manual control lever 7 extends out of the machine head 1 and passes through the worktable. A linkage device for controlling the manual control lever 7 is mounted on the worktable. During operation, when it is necessary to manually lift the presser foot, the operator applies force to the bottom end of the manual control lever 7 extending out of the worktable through the linkage device. The manual control lever 7 drives the L-shaped rocker arm 401 to rotate around its rotating rod inside the machine head 1. When the L-shaped rocker arm 401 rotates, it drives the connecting rod assembly 3 to move, causing the presser foot 2 to lift upward. When the force applied to the manual control lever 7 is removed, the presser foot 2 moves downward along the sliding track of the machine head under the restoring force of the spring, pressing down the fabric again. The manual control lever 7 can serve as a backup operation method to ensure that the sewing machine can perform presser foot lifting operations, avoiding sewing work interruptions due to equipment failure, and improving the reliability and continuity of equipment use.

[0033] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0034] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model.

Claims

1. A presser foot lifting device for a sewing machine, comprising a presser foot (2) mounted on a machine head (1), and a linkage assembly (3) for lifting the presser foot (2) in conjunction with the machine head (1), characterized in that: The machine head (1) is provided with a lifting foot transmission mechanism (4) that is connected to the connecting rod assembly (3) and a cam (5) for driving the lifting foot transmission mechanism (4) to lift the foot (2). The cam (5) is provided with an arc-shaped driving surface (501) on its periphery for adjusting the lifting height of the foot (2).

2. The presser foot lifting device for a sewing machine according to claim 1, characterized in that: The lifting foot transmission mechanism (4) includes an L-shaped swing rod (401) rotatably mounted in the machine head (1) via a rotating rod, with one end rotatably connected to the connecting rod assembly (3), and also includes a moving rod (402) slidably mounted via a limiting block (4010), with one end of the moving rod (402) being throttle-connected to the L-shaped swing rod (401).

3. The presser foot lifting device for a sewing machine according to claim 2, characterized in that: One end of the moving rod (402) is fitted with a roller (404) via an assembly block (403), and the roller (404) abuts against the arc-shaped driving surface (501).

4. The presser foot lifting device for a sewing machine according to claim 2, characterized in that: A first tension spring (405) is fitted between the moving rod (402) and the limiting block (4010) to ensure that the roller (404) always abuts against the arc-shaped driving surface (501).

5. The presser foot lifting device for a sewing machine according to claim 2, characterized in that: A connecting block (406) is fitted on one end of the movable rod (402) that is connected to the L-shaped swing rod (401). A limiting connecting rod (407) is fitted on the connecting block (406). One end of the L-shaped swing rod (401) is slidably disposed in a groove (408) opened on the limiting connecting rod (407).

6. The presser foot lifting device for a sewing machine according to claim 5, characterized in that: A second tension spring (409) is fitted between the connecting block (406) and the L-shaped rocker arm (401) to ensure that one end of the L-shaped rocker arm (401) located in the slide groove (408) is always in contact with the slide groove (408).

7. The presser foot lifting device for a sewing machine according to claim 1, characterized in that: The linkage assembly (3) includes a first linkage (301) rotatably connected to an L-shaped swing arm (401), and a second linkage (302) rotatably connected to the first linkage (301) and rotatably mounted on the machine head (1) via a rotating rod. A linkage column (201) cooperating with the second linkage (302) is provided on one side of the pressure foot (2). The pressure foot (2) is slidably mounted on the machine head (1) via a spring.

8. The presser foot lifting device for a sewing machine according to claim 1, characterized in that: The machine head (1) is equipped with a servo motor (6) for driving the cam (5) to rotate on one side. The servo motor (6) is controlled by a controller set on the machine head (1).

9. The presser foot lifting device for a sewing machine according to claim 2, characterized in that: The L-shaped rocker arm (401) is rotatably equipped with a manual control lever (7) for driving the L-shaped rocker arm (401) to rotate. The bottom end of the manual control lever (7) extends out of the machine head (1) and passes through the worktable.

Images